Closure construction for containers



June 29, 1965 G. A. MOORE I CLOSURE CONSTRUCTION FOR CONTAINERS Filed Oct. 2. 1961 INVENTOR ATTORNEY United States Patent 3,191,847 CLOSURE CONSTRUCTION FOR CONTAINERS George Arlington Moore, New York, NY. (910 Lake Shore Drive, Chicago, Ill.) Filed Oct. 2, 1961, Ser. No. 142,366 9 Claims. (Cl. 229-37) This invention relates to containers made of foldable sheet material and is more particularly concerned with improvements made in the utility end closure of the container and that maybe formed of folded integral elements provided with surfaces of thermoplastic film or dry adhesive treated in such novel manner that the resultant closure formed is rendered air and liquid tight, yet being well adapted to facilitate its being opened cleanly by hand and without causing any deleterious effects to the container or its closure formed elements, thus affording their further use for restoring the closure in substantially tight condition.

Conventional containers ,suchas folding cartons and other types made of paperboard have limited scope for product keeping ability without resorting to the use of augmenting materials such as inner liners, inserted preformed bags and overwrappings. Faults in the construction of their end closure and opening arrangements are Well known. For these reasons the industry is expending great effort in research and development to improve on these containers by lining the interior surfaces of the paperboard with thermoplastic film material. However, with respect to the end closure, should it be heat sealed in a manner to be rendered tight, it can not be opened in anymanner that will prevent such material mutilation of its structure as to make it useless for effecting a periodical reclosure of the container in order to protect its remaining contents. It is generally known that when two thermoplastic film surfaces are brought together and being heat sealed to constitute seams in a container the original meeting surfaces of these seams can not be surface separated. To the contrary, in such attempt the paperboard component supporting the plastic will split apart or tear the combined plastic film from the nap surface of the paperboard thus multilating it, This also applies to seams formed by any type of meeting surfaces of thermoplastic film to the Surface of the paperboard.

' It is a general object of the present invention to provide an improved end closure construction for containers that is formed in'a novel manner to be and liquid tight, yet having novel embodiments that enables the closure to be cleanly opened without multilating the closure forming elements and again use them for efficicntly reclosing the container.

- It is a more specific object of invention to provide the seam forming'surface areas of the closure forming elements with selective surface releasing treatment means effective to enable the constructed and sealed closure.

to be cleanly seam separated upon opening the container. Another object of the invention is to provide novel coasting means whereby in the structural form of a container, selected areas of its walls may be firmly bonded togetherwith adiacentareasthereof being cohered,.both in seam forming relationship, the latter'coalesced areas being stabilized in union by the coaching bonded areas. 7 A further object of the invention is to provide a closure construction integral with the body side walls of the container and having structural means to maintain major seam formed areas of the closure under constant compression, these areas being adapted to be cleanly separated apart upon opening the closure for container dispensing purposes.

These and'other objects of the invention .will be evident upon a consideration of the following description of the preferred embodiments used to illustrate the invention and by reference thereto in the accompanying drawings, in which FIG. 1 is a fragmentary view in perspective of a container showing its closure forming elements with portions partially folded prior to being fully closed.

FIG. 1a is an enlarged fragmentary view in cross section of the treated substrate that may be utilized for making the container embodied with the closure.

FIG. 2 is a fragmentary view in perspective showing the container with the completed end closure construction.

FIG. .3. is an exaggerated enlargedfragmentary view of the closure in cross section taken on line 33 in FIG. 2 and showing the technical aspects of the seam formed structure.

FIG. 4 is a fragmentary view in perspective of the container and showing the initial steps taken in opening the sealed closure.

FIG. 5 is a small fragmentary view in perspective showing the embodiment of a modification made to certain treated surface areas of the closure forming elements.

' FIG, 6 is a fragmentary view in perspective of the container of FIG. 5 and showing the modified sealed closure in a stage of being opened.

FIG. 7 is an exaggerated enlarged fragmentary view in cross section of the substrate material shown with a hypothetical patterned surface treatment that may be utilized in construct-ing other types of scam forming arrangements contemplated by the invention.

An embodiment'of thenovel dispensing closure comtheclosure forming elements as will be. herein after described for constructing the utility and closure on such containers.

As previously mentioned, folding cartons in major instances must depend upon other augmenting materials in order to provide some measure of protection for its intended product. The folded flaps and spot glued nature of the formed end, closures of these cartons necessitates the use of these added sheet materials. Furthermore, no practical means is provided for opening these end closures without mutilating the closure thus making these fiaps useless for reclosing the opened carton.

The closure construction contemplated by the present invention eliminates these faults herein before mentioned. Referring now to FIG. 1 of the drawings, there is illustrated a container body 5 embodied with the closure form.-

ing elements 7 and 8. Thesheet material of which the container is formed is preferably paperboard A of suitable thickness and shown in FIG. 1a faced with any suit-' clear nitro-cellulose lacquer having no thermoplastic properties and low in dry solids has been found suitable for such application; hereinafter to be referred to as the film median b.

Again referring to FIG. 1 an opposing pair of the' closure forming elements 7 are shown in folded marginally reversed superposed relationship to bring the respective coated surface marginal portions 12 in up-faced position to constitute panel seating ledges disposed inwardly and downwardly of each depending side wall, the thermoplastic film a on the up-faced margins 12 is overcoated with the film median b. The end edges 15 of the flattened portion of the ledges 7 are disposed in alignments with the groove 13 which defines the hinge of the full closure forming panel element 3 disposed transversely of the ledges. This panel is provided with a projected end flange 10 defined by the groove 9. The end edge of the flange is provided with a pair of opposed outwardly and downwardly sloping edge portions 11 utilized for a purpose hereinafter to be described. The interior surface of the panel and flange is provided with the thermoplastic film a. The groove 9 is overcoated with the film median b slightly bled outwardly of the groove over its parallel corner edges. A surface of the flange spaced upwardly of the groove may be overcoated with the film median b. The front side wall of the container is provided with a straight end edge 14. By folding the panel 8 inwardly and downwardly upon the ledges in compressed relationship the end edges 16 of the ledges are brought into edge to face abutments upon the plastic face of the front side wall of the container, the groove 9 of the panel embracing the end edge 14 thereof. While the panel is flatly pressed downwardly thereupon, its projected flange 10 is folded downwardly and inwardly upon a corresponding exterior surface of the front side wall. Thus the mechanics of folding the closure is completed. It will be observed by viewing FIG. 3 that the film median b is interposed between two layers of the film a these stratified layers being disposed in firm contacted surface relationship by the upward bearing pressure exerted by the ledges 7 imposed upon the downwardly compressed panel 8. It is further seen that the median film b is also interposed between the surface of the end edge 14 and film a on the panel. In addition, the median film b is interposed between the exterior surface of the side wall and film a on the flange in downwardly spaced relation to its top corner end 17.

In order to seal the closure structure and render it air and liquid tight it is necessary to maintain pressure imposed inwardly upon the flange 10 opposed by like pressure imposed upon the opposite side wall at and below the corner end 13' of FIG. 2 of the closure, and simultaneously maintain downwardly imposed pressure upon the exterior surface of the panel 8. While so confined, heat ranging in temperature from 350 to 450 F. regulated according to the time cycle required may be utilized for activating the plastic seam forming areas of the closure and thereby bond the closure in seam forming relationship as illustrated in FIGS. 2 and 3. If desired, the plastic film may be preactivated by radiant heat prior to the folding of the closure forming panel 8. By so doing the time cycle for sealing the closure may be shortened.

The sealed structure of the closure can best be understood by viewing FIG. 3 wherein the end edges 16 of the compressed ledges 7 are heat butt welded to the plastic film a on the opposing side wall. Likewise the opposite end edges 15, shown in FIG. 1, are butt welded in the same manner upon the other opposing side wall, thereby sealing these end edges off from being exposed in the interior of the container. The seams formed that unite the panel 8 to the ledges 7 and end edge 14 are cohered in united relationship by virtue of the median film b. The flange 10 however is firmly bonded upon its opposing side wall as shown at the limited seam area 18, and this particular seam formed co-acts to keep the cohered seams in tightly sealed united relationship. The lower part of the flange is cohered upon the side wall to keep the flange end flatly disposed as shown in FIG. 2. The permanently compressed ledges co-act to form strong structural reinforcements in completing the closure construction.

The constituted hermetic closure has been constructed in a manner to facilitate its clean opening for container dispensing purposes. This may be easily accomplished by releasing the lower end of the flange 10, FIG. 2, which will cleanly yield from its attached wall surface as shown by the dotted lines 19 in FIG. 3. This provides finger grasping means With which to pull the flange outwardly which shears its bonded seam 18 loose from the side wall. Then by pulling on the flange upwardly as shown in FIG. 4 the panel portion 8 cleanly separates from its cohered seam formed relationship with the end edge 14 and ledges 7. The plastic film 11 remains intact upon the opened elements by function of the median film b which remains intact upon the surface 12 of the exposed ledges 7. The clean shear of the seam 18 of the flange is made possible by the shielding influence of the adjacent border defining edges of the median film b. The adjacent surface areas of the paperboard material of the closure formed elements is prevented from being torn or split by the nap surfacing protective quality of its intact thermoplastic film.

The opened elements are therefore left in condition for restoring the closure in the manner hereinbefore described. The exception, however, is to insert the flange of the panel inside of the front side wall, whereby the sloping end edges 11 of the pushed in flange will shear apart the welded end edges 16 of the ledges which will serve to bind or wedge the flange in position to retain the panel compressed downwardly upon the resisting ledges 7. Thus, the restored closure is constituted to keep the remaining product in the container further protected.

The present invention further contemplates a novel method of providing coacting means for reinforcing the cohered united areas of the heat sealed seams of the closure construction. The end result of this is illustrated in FIGS. 5 and 6 whereby the median film b is applied upon the thermoplastic surfaces 12 of the ledges 7 in a manner to leave a surface exposed area of the film a bordered on two sides 0 of the median film. Such surface treatment may be made upon these indicated surface areas on the container forming blank. Upon heat sealing the closure in the manner hereinbefore described and illustrated in FIGS. 2 and 3, the seams formed uniting the panel 8 to the ledges 7 are strengthened by a sectionally and jointly disposed firmly bonded portion extended longitudinally of the seam between the welded end edges 15 and 16 thereof. The adjacent united areas of the seam being cohered and stabilized by the coacting effects of said bonded portions thereof. Thus formed, the closure constructed by utilizing this method of surface treatment is constituted to withstand very rough and abusive handling. To better facilitate the method of applying the coating of the median film upon the blank of the containers, the film b may be applied upon the end edge 14' and upon a selective exterior surface portion of the front side wall 5' as shown at the locations b on the formed container illustrated in FIG. 6, which shows the closure in a stage of being opened manipulated in the same manner described for the illustration given in FIG. 4. As the panel is pulled upwardly as shown in FIG. 6 the firmly bonded line seal portion 21 will shear apart in clean and orderly manner because of the function provided by the previously mentioned parallel border line edges c of the adjacent median film b, the cohered united areas are separated cleanly thereby leaving the film a intact upon the panel and ledges on each side of the sheared area 21.

For purposes of further illustration of the thematic aspects of the invention it can be observed that the medlan plastic film material I) as applied (FIG. 1a) is adhered upon the surface of the thermoplastic film surface a of the substrate, it being non-toxic, odor and tack free. The ultimate seams formed of the substrate in this manner are rendered cohesive. Therefore, in order to preserve these seam formed areas tightly united it is necessary to provide one or more coactive firmly bonded seam formed area zones disposed in the particular structure such as the seam 13, FIG. 3 or as prepared in FIG.5, however, FIG. 7 illustrates the median film as may be applied in the surface form of a hypothetical pattern that may be shaped in any manner desired for constructing ultimate coactive seam forming areas in a container construction whereby unit parts of its closure to be formed may be selectively bonded permanently together and other parts to be cleanly separated. Hence, this method process may be utilized for useful purpose in forming various other modified structures of'container closures. The invention will suggest such modification-s and adaptations, such within its scope of teaching.

Having thus described my invention in what I now believe to be comprehensive embodiments, what is claimed 1s:

1. In a container formed of paper lined with thermoplastic film material, and having end closure forming elements folded and secured in heat sealed seam forming relationship, a pre-applied pattern coating of non-thermoplastic filmmaterial upon selected surface areas of the thermoplastic film material on said closure forming elements, said film of non-thermoplastic material disposed between the opposed meeting surfaces of the thermoplastic film material upon folding said elements into closure formation being in cohered seam forming relationship as a result of the action of imposed heat and pressure upon said surfaces, said relationship being secured by other firmly bonded adjacent surface areas of said folded closure formed elements, said cohered seam surfaces being rendered cleanly releasable upon the severing of said firmly bonded surface areas of the closure formation when opening the container.

2. In a container, the elements set forth in claim 1 wherein said closure forming elements include a pair of compressible seating ledges, the upper disposed marginal surfaces thereof having said pre-applied coating of said non-thermoplastic material thereupon, and a closure panel, said panel having a projected portion thereof adapted when folded and bonded for securing the panel upon said ledges in compressed and cohered seam forming relationship.

3. In a container formed of paper and combined plastic sheet material having thermoplastic properties, said container having end closure forming elements adapted for being folded and tightly heat-sealed into closure forming relationship, said elements comprising an end closing panel and flange thereof having its interior surfaces covered with thermoplastic film material, and a pair of inwardly folded seating ledges, said panel being folded inwardly and downwardly flatly upon said seating ledges, the exterior marginal surfaces of said ledges having a combined covering of thermoplastic film material overcoated with a pre-applid pattern of non-thermoplastic film forming material, whereby under heat and pressure said prepared surfaces of the ledges and corresponding film surfaces of said panel are blended together in cohered seam forming relationship, said panel flange being folded and firmly bonded upon a prepared limited area of the exterior surface of an adjacent side wall of the container in order to maintain said seam forming relationship.

4. In a container, the end closure thereof as set forth in claim 3 wherein the firmly bonded surface area of said flange and side wall is limited by a pre-applied pattern coating of non-thermoplastic material disposed upon the exterior surface of said side wall, whereby upon severing said bonded surface area to release the flange from the side wall said cohered seam formed surface areas of the closure are readily separated without mutilation in opening the container, after which, the elements of the opened closure may be re-folded and retained in container closing condition.

5. In a container formed of foldable sheet material surfaced with thermoplastic film material, and being provided with integral end closure folded elements which include a cover panel and a pair of opposed cover panel seating ledges, the cover panel having means for maintaining the folded construction of the end closure of the container: a pre-applied coating of non-thermoplastic material upon selected surface areas of the thermoplastic film on said end closure elements, whereby upon imposing heat and pressure upon the seam forming surfaces of said folded end closure elements the heat activated meeting surfaces of thermoplastic film selectively treated are adhered together in seam forming relationship maintained by an extended firmly bonded sectional part of said cover panel not so treated.

6. The method of forming an end closure of a container having fourside Walls arranged in opposing pairs and provided with'closure forming elements consisting of a pair of opposed panel seating ledges and transversely thereof at least one cover panel having an end flange, said elements being provided with interior surfaces of thermoplastic film material, said method comprising pre-applying a pattern coating of non-thermoplastic film forming material upon selected surface areas of the thermoplastic film disposed upon said pair of panel seating ledges and panel end flange associated surface areas, folding said ledges into closure forming position thereby bringing said pre-applied coated surfaces thereof into up-face position, folding said cover panel inwardly and downwardly upon said up-faced surfaces of the ledges, then folding said end flange of the folded panel downwardly and inwardly upon its associated side wall of the container, applying heat and pressure upon said cover panel and flange whereby said ledges at least in part are cohesively adhered with r the corresponding surface areas of said cover panel, said flange thereof in part being firmly bonded to its associated opposing side wall of the container in seam forming relationship, the firmly bonded seam formed section of the closure providing the means for maintaining the defined cohesively adhered seam formed areas thereof.

7. In a container formed of foldable sheet stock coated on one side with a thermoplastic film, said container having four side walls bearing said film on their inner faces, van end closure for said container comprising a reversely folded element integral with each of two opposed side walls of the container, said element being foldable along the upper edge of its respective side wall into a plane transverse to said side wall, the upper face of said element bearing said thermoplastic coating, a cover panel integral with a third side Wall of said container between said opposed side walls, said cover panel being foldable along the upper edge of said third side wall into superposed relationship with said elements, the under face of said cover panel bearing said thermoplastic coating, and a coating of non-thermoplastic material between each of said elements and said cover panel, said nonthermoplastic coating being arranged in a pattern such that in a continuous region extending for the full length of each of said elements the thermoplastic film on the upper face of said element is exposed to the thermoplastic film on the under face of said cover panel, whereby upon application of heat and pressure to said superposed cover panel and elements a firm bond is established in said continuous regions and a readily separable cohered seam is established in the regions occupied by said non-thermoplastic coating.

8. In a container, the elements set forth in claim 7 wherein said continuous region corresponds to a central portion of said element, and said non-thermoplastic material occupies two marginal regions flanking said continuous region.

9. In a container, the elements set forth in claim 7 including a flange integral with and foldable along the free edge of said cover panel, said flange being brought into overlying relationship With the outer face of Said fourth side wall when said cover panel is folded down upon the upper edge of said fourth side wall, said flange bearing said thermoplastic film on its inner face, and a film of non-thermoplastic material covering a margin of the inner face of said flange adjacent its free end, said uncovered portion of said flange being firmly bonded to said fourth side Wall by said thermoplastic film as a result of the application thereto of heat and pressure to maintain the contact between said cover panel and said elements and the upper edge of said fourth side wall, and said marginal portion of said flange being in readily separable coherent relationship with said fourth side Wall as a result of said application of heat and pressure whereby said margin may readily be lifted away from said fourth side Wall preparatory to opening the container.

References Cited by the Examiner UNITED STATES PATENTS 2,099,166 11/37 Inman et a1. 22 9--S1 Moore 229-3.l

Wilcox 2297 Moore 22943 Steck 22951 Moore 2295l Moore 229-37 Moore 229-37 THERON E. CONDON, Primary Examiner. EARLE I. DRUMMOND, GEORGE o. RALSTON,

Examiners. 

7. IN A CONTAINER FORMED OF FOLDABLE SHEET SHOCK COATED ON ONE SIDE WITH A THERMOPLASTIC FILM, SAID CONTAINER HAVING FOUR SIDE WALL BEARING SAID FILM ON THEIR INNER FACES, AN END CLOSURE FOR SAID CONTAINER COMPRISING A REVERSELY FOLDED ELEMENT INTEGRAL WITH EACH OF TWO OPPOSED SIDE WALLS OF THE CONTAINER, SAID ELEMENT BEING FOLDABLE ALONG THE UPPER EDGE OF ITS RESPECTIVE SIDE WALL INTO A PLANE TRANSVERSE TO SAID SIDE WALL, THE UPPER FACE OF SAID ELEMENT BEARING SAID THERMOPLASTIC COATING, A COVER PANEL INTEGRAL WITH A THIRD SIDE WALL OF SAID CONTAINER BETWEEN SAID OPPOSED SIDE WALL, SAID COVER PANEL BEING FOLDABLE ALONG THE UPPER EDGE OF SAID THIRD SIDE WALL INTO SUPERPOSED RELATIONSHIP WITH SAID ELEMENTS, THE UNDER FACE OF SAID COVER PANEL BEARING SAID THERMOPLASTIC COATING, AND A COATING OF NON-THERMOPLASTIC MATERIAL BETWEEN EACH OF SAID ELEMENTS AND SAID COVER PANEL, SAID NONTHERMOPLASTIC COATING BEING ARRANGED IN A PATTERN SUCH THAT IN A CONTINUOUS REGION EXTENDING FOR THE FULL LENGTH OF EACH OF SAID ELEMENTS THE THERMOPLASTIC FILM ON THE UPPER FACE OF SAID ELEMENT IS EXPOSED TO THE THERMOPLASTIC FILM ON THE UNDER FACE OF SAID COVER PANEL, WHEREBY UPON APPLICATION OF HEAT AND PRESSURE TO SAID SUPERPOSED COVER PANEL AND ELEMENTS A FIRM BOND IS ESTABLISHED IN SAID CONTINUOUS REGIONS AND A READILY SEPARABLE COHERED SEAM IS ESTABLISHED IN THE REGIONS OCCUPIED BY SAID NON-THERMOPLASTIC COATING. 